Hay meadow species for sandy dry soil would suit. There's a ton of suppliers for wildflower seed in the UK, but I'd highly recommend to use one that's reputable. You can either go for seeds with UK provenance or plant legumes to give pollen and nectar resources. Or you could collect local seed from meadows near you, but that's a lot more work!
Maintenance would be cutting once a year (September) and allowing the seed to fall (to allow natural regeneration) before collecting the hay. Would that be low maintenance enough for you? The cutting and picking up the hay does take a bit of time.
Let me know if you'd like to know more on establishing a wildflower meadow, it's my research specialty.